#neutrons — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #neutrons, aggregated by home.social.
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COW DISTINGUISHES SQPR FROM PENROSE’s Gravitational Localization:
COW Experiment Potentially DISTINGUISHES SQPR
In the 1970s I told Sir Roger Penrose (among others at Stanford) about the basic idea of SQPR. Penrose published in the 1980s the Gravitationally Induced Spontaneous Localization theory which applies the time-energy uncertainty (TEU) relation to spacetime. The two Objective Reduction theories are very different, because they have different collapse mechanisms.
In particular at cosmological scale, SQPR predicts observed facts, such as Dark Matter and Dark Energy, whereas the Penrose theory does not.
The theories also make very different predictions in the lab relative to Quantum Mechanics, and also relative to each other. Let’s explore.
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Diósi-Penrose Objective Reduction (DPOR) model is a hypothesis proposing that quantum wavefunctions collapse spontaneously due to gravitational instabilities caused by mass superposition. It has the advantage of tying in gravity and Quantum Mechanics (QM) in the simplest manner.
Core Concepts
- Gravity and Superposition: When a massive object exists in a superposition of two different locations, the distribution of its mass creates a simultaneous superposition of two distinct spacetime geometries. (At least that’s what the formalism of Quantum Mechanics predicts!) [1, 2]
- Spacetime Conflict: General relativity requires a single, well-defined spacetime metric, creating a fundamental clash with quantum superposition. [1]
- Objective Reduction: Rather than needing an external observer or measurement to trigger a collapse, gravity forces the system to resolve itself into a single state. [1, 2]
- Timescale: The lifetime of the superposition is inversely proportional to the gravitational self-energy difference between the states. The exact expression obtained by applying the TEU. The duration until collapse is inversely proportional to the difference in gravitational energy between the two different locations (and proportional to Planck constant, of course! It’s direct TEU!)
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In the Colella-Overhauser-Werner (COW) experiment, realized in 1975, thermal neutrons enter a silicon crystal Mach–Zehnder interferometer. When the interferometer is tilted by an angle theta relative to the horizontal, one arm (Path A) is at a higher gravitational potential than the lower arm (Path B).
It turns out that the energy of the quantum state in the upper branch, Path A, is different in composition from that of the lower branch, Path B. This can be physically demonstrated through the apparition of shifting interference fringes. The effect has been observed.
The reasoning is fascinating: one makes a number of assumptions, simplest and most natural. Those assumptions bring us to a shifting interference pattern shifting in a peculiar way, which is observed. Therefore one is entitled to deduce that the assumptions made were correct, and this tells us many things about matter waves.and in particular how long the guiding waves are. It may also enable to demonstrate in the lab the existence of Objective Reduction theories, which extend understanding beyond Quantum Mechanics.
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Penrose’s Model Makes Experimental Predictions:
If one plugs the usual numbers in, considering self-gravitation of the neutron, one gets millions of years for Penrose collapse to happen.
However for a single neutron interacting with Earth’s massive gravitational field, going both down a ground branch of the interferometer (B) and the elevated one (A), the difference in gravitational energy is mgh, where g is the usual gravitational acceleration at sea level, m is the mass of the neutron, and h is how high A is above B.
If we extend the COW experiment using large molecules (like fullerenes or 10^4 atoms macromolecular clusters) or Bose–Einstein Condensates (BECs) instead of single neutrons, mgh scales up by 10^4 to $10^6. Then the collapse time drops precipitously from millions of years to milliseconds or microseconds—falling right inside the passage duration of the experiment!
https://quantumnano.at/research/universal-matter-waves/why-matter-waves
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Penrose does not suggest a plausible mechanism to cause collapse.
DPOR is a particular case of Objective Reduction (OR) models, where one does away with the silliness of an observer and “measurements”.
The other model is SQPR, which ignores gravity, but not matter abundance and the QM state (for example Quantum amplitudes) it is in…
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The SQPR Shift:
- If localization is independent of the background gravitational field g and depends instead on the density of surrounding matter fields (and the probability of guiding-wave truncation/shedding), then tilting the interferometer or placing it in a deep gravitational potential well will not alter the intrinsic collapse rate.
- An extended COW experiment conducted at sea level versus one conducted in microgravity (e.g., on the ISS) or on the Moon would yield the exact same decoherence rate in SQPR.
- Under Penrose, microgravity suppresses collapse; under SQPR, space microgravity leaves the collapse rate unchanged because matter-field interactions and guiding-wave limits remain invariant.
[Camping in Sierra Nevada; Post will be improved in future and computations made explicit…]
Patrice Ayme
#Consciousness #COWExperiment #Founndations #Interferometry #Localization #Neutrons #Penrrose #Philosophy #Physics #QuantumMechanics #Science #SQPR -
A Benchtop Neutron Generator for the Home Reactor
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Scientists at the Research #NeutronSource Heinz Maier-Leibnitz (FRM II) investigated, for the first time, #coralbleaching processes directly in living corals. 🪸Using #neutrons, they visualized structural changes during bleaching: http://go.tum.de/326347
📷iStock/ Nastco
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Students at #SNOLAB are starting to engage in our common orientation for research experiences. One particle that comes up really early is the #muon. Students often don't learn about subatomic particle properties other than #electrons, #protons, and #neutrons until late in university. I made this video explicitly to help early-career students get familiar with the muon and see how it was the first direct test of the #relativity of time:
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Après la supernova, après la kilonova : la superkilonova
https://www.ca-se-passe-la-haut.fr/2025/12/apres-la-supernova-apres-la-kilonova-la.html
#science #astronomie #astrophysique #espace #tech #étoiles #supernova #kilonova #superkilonova #neutrons #fusion #trounoir #ondesgravitationnelles -
The new ErUM Transfer research project, AlaAF, aims to develop methods for manufacturing particulary light yet extremly resilient #aluminium components for #aerospace using industrial #3Dprinting: http://go.tum.de/415949
📷Dr. V. Ryukhtin / NPI Rez
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Manchester to Copenhagen by train for #ICNS025. Great journey for tunnels and bridges.
#AcademicChatter #AcademicTravel #FlightFree #StayGrounded #Climate #GianlucaGrimalda #Neutrons #ICNS #greenacademiles #SustainableTravel
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Production and measurement of the extremely heavy, neutron-rich hydrogen isotope ⁶H achieved for the first time in an electron scattering experiment at the Mainz Microtron accelerator MAMI / Result shows stronger than expected interaction between neutrons within the nucleus 👉 https://press.uni-mainz.de/new-method-to-produce-an-extremely-heavy-hydrogen-isotope-at-the-mainz-microtron-accelerator-mami/
#NuclearPhysics #ParticleAccelerator #hydrogen #spectrometer #nucleus #neutrons
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Let There Be Neutrons! Hadronic Photoproduction from a Large Flux of High-energy Photons: https://iopscience.iop.org/article/10.3847/1538-4357/adb1e3 -> New theory suggests stars dissolve into #neutrons to forge heavy elements: https://www.lanl.gov/media/news/0325-star-dissolution - a theoretical framework proposes high-energy jets to advance understanding of challenging physics.
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The smallest-ever force field map of nature.
Physicists have mapped the forces acting inside a #proton, showing in unprecedented detail how #quarks—the tiny #particles within—respond when hit by high-energy #photons.
The new result breaks down #space and #time into a fine grid, allowing simulating how the strong force—the fundamental interaction that binds quarks into #protons and #neutrons—varies across different regions inside the proton.
#physics
https://phys.org/news/2025-02-scientists-proton.html -
[Joyeux anniversaire, #XMMNewton ! 🥂 🎉 ] 25 ans. Cela fait 25 ans que l' #Observatoire XMM-Newton de l' European Space Agency - ESA lancé par une fusée #Ariane5 scrute notre #Univers dans le domaine des rayons X.
Récemment, les données acquises par cet observatoire ont permis de comprendre l'origine des #aurores X aux pôles magnétiques de #Jupiter, de contraindre les #théories sur l'intérieur des étoiles à #neutrons, de révéler de gigantesques #éruptions en périphérie d'un #TrouNoir supermassif, etc : https://www.esa.int/Science_Exploration/Space_Science/XMM-Newton/XMM-Newton_celebrates_25_years_of_breakthroughs
Depuis quelques années, l'avenir se dessine, avec la mission #Athena, et le #spectromètre de nouvelle génération #XIFU ...
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First coherent picture of atomic #nucleus made of quarks and gluons
#Quarks and #gluons were used to describe properties of atomic nuclei, which until now had been explained by #protons and #neutrons.
“Until now, there have been two parallel descriptions of atomic nuclei, one based on protons and neutrons which we can see at low energies, and another, for high energies, based on quarks and gluons" This work ""managed to bring these two so far separated worlds together"
https://press.ifj.edu.pl/en/news/2024/10/15/ -
Watch the second episode of the “close-up“ series, where our student Nina visits the research neutron source Heinz Maier-Leibnitz (FRM II), to learn more about the research with #neutrons and #positrons: http://go.tum.de/139820
#batteries #aerospace #cancertreatment
🎥@Prolehre
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Researchers at the Research on geological deposits at the FRM II characterized the networks of #micropores in #sedimentaryrocks to find out whether they are suitable as impermeable layers for #nuclearwaste repositories and #CO2storage sites: http://go.tum.de/216311
📷B.Ludewig
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Happy 20th anniversary to our Research Neutron Source Heinz Maier-Leibnitz (FRM II)! Since 2004, it plays a key role internationally in providing #neutrons for research, industry, and medicine, generating publications in e.g. #quantumtechnologies, #mobility and #climate & environment: http://go.tum.de/158733
📷 A.Eckert
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Christian Pfleiderer, Professor of #Topology of Correlated Systems, is the new Scientific Director of Research Neutron Source Heinz Maier-Leibnitz (FRM II) from January 1, 2024. 👏 He aims to make the research accessible to the entire #scientificcommunity: http://go.tum.de/509989
📷A.Eckert
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PSI researchers are using #neutrons to make changes in #battery #electrolytes visible. The analysis enables better understanding of the #physical and #chemical processes and could aid in the development of #batteries with better characteristics.
#Physics #Chemistry #Technology #sflorg
https://www.sflorg.com/2023/10/phy10262301.html -
It can’t be such a bad day when you get a full 22 degree circle, sundogs, an upper tangent arc and a circumzenithal arc hanging high over your experiment. And the beam is up. #ISIS #neutrons #StrangeIce
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Using #neutrons to see the additive manufacturing process at the #atomic level, scientists have shown that they can measure strain in a material as it evolves and track how #atoms move in response to stress.
#MaterialScience #sflorg
https://www.sflorg.com/2023/10/ms10132301.html -
Double Magic Cancels Itself Out?
#Oxygen #Oxygen28 #neutrons #atom #element #physics #chemistry
https://www.nature.com/articles/d41586-023-02713-3 -
Neutrons can help stop cancer from hijacking a metabolic highway, according to a new study by ORNL scientists. The study reveals how an enzyme called PDXK uses vitamin B6 to make a molecule called PLP, which is vital for the one-carbon metabolism pathway in cancer cells. The study also provides clues for designing new drugs that can block PDXK and starve the cancer cells of their resources.
